Theoretical study of the accuracy of the height dimensions of forgings for upsetting and closed forging operations, taking into account the choice of forging and pressing equipment

Abstract

The use of low-waste technologies in blank production in the process of performing cold die forging (CDF) operations involves the use of various types of presses, such as crank, hydraulic and screw ones. The range of forging and pressing equipment is quite wide, so the problem of rational use of a particular type of press always arises. Any press must provide the necessary force to deform the original workpiece. Technological processes of metal forming are accompanied by high specific forces of resistance to deformation of materials, which is realized by the design features of the working link of forging and pressing equipment. It should be noted that one of the most important criteria influencing the choice of a press for performing CDF operations is the achievable accuracy of stamped forgings. Taking into account the design features of the types of presses, there are significant differences between them. These differences will be determined by the forging deformation conditions. The performed analytical calculation of error conversion coefficients for forgings during CDF operations makes it possible to evaluate the influence of the factors of the original workpiece on the accuracy of the height dimensions of the forging itself. The obtained graphic dependences for crank, hydraulic and screw presses show the relationship of conversion factors depending on the initial errors of the forgings and the rigidity of the forging itself to the accuracy of height dimensions. As a rule, the rigidity of a forging is determined by the ratio of diameter and height for the upsetting operation, but in the case of a closed forging, the radius at the edges must be taken into account. The article is devoted to a theoretical study of the height error of forgings for the operation of upsetting and closed forging, taking into account the used forging and pressing equipment.